Apparatus for hot vulcanizing seams in rubberized elements



July`13, 1965 M. P. F.GAMB|N 3,194,715 APPARATUS Fon HOT vuLcANIzING smus 1N nmasmzrznn ELEMENTS Filed Nov. 21, 1961 4-sheetssneet1 July 13, 1965 M. P. F. GAMBIN APPARATUS FOR HOT VULCANIZINGSEAMS IN RUBBERIZED ELEMENTS Filed Nov. 21. 1961 4 Sheets-Sheet 2' July 13, 1965 M. P. F. GAMBxN 3,194,715

AFPARATUS FOR HOT VULCANIZING SEAMS IN RUBBERIZED ELEMENTS Filed NOV. 21, 1961 4 Sheets-Sheet 5 @Gwwm United States Patent APPARATUS FOR HOT VULCANIZENG SEANS IN RUBBERIZED ELEMENTS Michel Philippe Franois Gambia, 13 Rue Souiot, Paris, France Filed Nov. 21, 1961, Ser. No. 153,822

Claims priority, application France, Dec. 20, 196i),

848,526 2 Ciams. (Cl. 156-583) It is known that in order to hot vulcanize seams in thin rubberized elements, such as, for example, sheets of rubber and rubberized fabrics united by means of a suitable raw rubber, use is commonly made of presses in which the frame is in the form of a swan neck and in which a heating plate not only ensures the heating of the seam to be vulcanized, but also the holding in place thereof on the table of the press-which table does not ordinarily perform a heating action-owing to the interposition of a suitable jack between said heating plate and the overhanging part of the neck of the frame of the press.

In this way, seams or welds of small dimensions are obtained and when the seam has a length exceeding that of the heating plate it is necessary to eect a plurality of successive operations.

It is necessary to observe that, when a seam uniting two pieces of rubberized fabric is vulcanized, these pieces of fabric project on the press table on both sides of the heating plate and that the holding in place of said two pieces of fabric must necessarily be achieved by a clamping action or pressures exerted on the areas adjacent the seam and not on the parts actually being welded (although, in fact, these parts are nearly always more compressed because of the extra thickness), inasmuch as due to the action of the heating operation the raw rubber melts before becoming vulcanized and it is therefore important to avoid rigorously any relative slipping of one of the pieces of fabric with respect to the other liable to cause a decrease in width, and consequently in strength, of the seam.

In the case of vseams of great length and, moreover, having a generally rectilinear line, the first idea which comes to mind with the aim of reducing the number of operations (and, if possible, effecting the vulcanization of the whole of the seam in a single operation) is the replacement of the conventional heating plate of small dimensions by a heating beam installed in a press whose frame would have a corresponding capacity and would be provided with a suitable plurality of jacks, the action of which is suitably distributed over the entire length of the beam.

The practical carrying into eifect of this idea, however, comes up against two difficulties. p

In the rst place, the cumbersomeness and the weight of pieces of rubberized fabric of great length and also the fragility of the temporary cemented joint to be vulcanized do not permit of locating the axis of the seam exactly below the axis of the heating beam. There always continues to exist a slight over-all Obliquity on which there are superimposed slight local divergences with respect to the theoretical axis on the seam and this results in the need for a broad heating beam.

In the second place, the need to hold the two pieces of rubberized fabric to be welded tightly at their areas adjacent the seam, which are obviously not provided with any raw rubber, leads to an additional increase in the width'of the heating beam so that the edges of said beam may bear effectively on said areas devoid of raw rubber in order to avoid any relative slipping of said pieces of fabric during the melting of the raw rubber, as explained y ICC above, but the result is a considerable increase in the area of rubberized fabric heated. Th-e fabrics always contain a certain amount of water and the amount of steam produced is proportional to the area of the heated surface. In the case of a heating surface having a considerable area, which is the case with the beam widened as stated above, the amount of steam produced will have a value such that it will cause the formation of blisters in the unheated parts of the two pieces of rubberized fabric, in which blisters the rubber becomes detached from the fabric, and experience has shown that fabric which has become de-rubberized locally in this way tears afterwards at the places where said blisters are located (probably because a considerable local stress exerted on a bre is not distributed by the rubber between said overloaded bre and the adjacent fibres). When the heating surface is small, which is the case with conventional heating plates, which are of small dimensions, the same phenomenon of production of steam occurs, but the consequences thereof are tolerable. However, it should be understood that the improved arrangement which will be described hereinafter with the aim of alleviating the above-described drawbacks is also applicable with a certain benefit to heating plates of small dimensions, or, in other words, that the invention is absolutely independent of the length of the heating beam, whether said length is very considerable or, on the other hand, very small.

The present invention relates to an improved apparatus, involving, of course, the use of a swan-neck press the frame of which has dimensions adapted to said apparatus and is equipped correspondingly in a suitable manner, permitting of vulcanizing a generally rectilinear seam of great length in a single operation, characterized by:

(l) The combination of a narrow heating means having only a width compatible with, but not in excess of, the width of the seam to be vulcanized, and of two means framing said heating means but without any direct or indirect heating capacity, the function of which consists solely in respectively holding iirmly each of the pieces of fabric being welded by exerting a suitable pressure on an area of rubberized fabric devoid of raw rubber and adjacent the seam, and,

(2) The use of a mechanical connection between these three means and the overhanging part of the swan-neck of the press frame, said connection permitting the heating means to be brought Vinto exact coincidence with the seam disposed on the press table and thereafter producing the necessary pressures.

Many constructional forms of an improved apparatus complying with the principle of the invention can be envisaged and, out of this large number of constructions, several preferred embodiments will now be described by way of non-limitative example with reference to the accompanying drawing, in which:

FIGS. l, 2 and 3 show a first example of an apparatus complying with the principle of the invention;

FIGS. 4 and 5 show a second example of such an apparatus;

' FIGS. 6 and 7 show a third example of such an apparatus, and Y FIGS. 8, 9 and 10 show a fourth example of such an apparatus.

Example 1 This first example of the application of the principle of the invention is shown in FIGS. l, 2 and 3, FIG. 1

' being a side view of the apparatus, FIG. 2 being a secwith a heating element such as shown in Saliisberg U.S.

Patent No. 2,175,031, issued October 3, 1939, having a width enabling it to cover, despite any over-all Obliquity and local divergences, the seam toA be vulcanized and also the areas of rubberized fabric which are devoid of raw rubber and by which said pieces of fabric must be irmly held during the vulcanizing process. y'

Below said broad heating beam designated by the reference PP there is a narrow strip of aluminum AA', the width of which corresponds, without any surplus, to that ofthe seam to be vulcanized. Said strip is attached to the heating beam PP by means of two transverse strap supports St each embracing one end of the beam PP', which ends are chamfered so that said strap supports St do not `interfere with perfect tting of the aluminum strip AA'. These strap supports St are arranged in such manner as toV give the suspension of the aluminum strip AA' a freedom such. that the latter can be shifted easily by means of the handles Z which are attached to beam Fi by shafts Z' as required by the effective position of the seam to be vulcanized. Moreover, on both sides of the aluminum strip AA' and suspended in the same manner with the same degree of freedom there are two strips I-I', consisting of material which is a poor conductor of heat, for example having an asbestos base, which strips can consequently be shifted with the same ease as the heating strip AA and placed parallel with said heating band as required by the over-all Obliquity of the seam to be vulcanized.

The strip of aluminum AA', by reason of the high thermal conductivity of this metal, transmits the heat to the seam to be vulcanized, it being an easy matter to control such transmission by incorporating thermocouples (not shown).

On the other hand, the lateral strips I-I of heat-insulating material ensure the holding of the pieces of rubberized fabric without any risk of undesirable heating.

This constructional form of an apparatus according to the invention obviously Veliminates the drawback of excess vapourisation of the water contained in the textile iibers forming the rubberized fabric, but it entailsthe heating of a beam having a large rnass and, consequently, may be considered in certain circumstances as costly from the `point of view of the consumption of energy required for heating it.

The examples described hereinafter give a solution which is more economical from this point of view.

Example 2 In this second example, shown in FIGS. 4 and 5, FIG. 4 being a bottom view of the apparatus and FIG. 5 being an end View in the direction of the arrow VII in FIG. 4 it will be seen that the apparatus in accordance with the principle of the invention comprises a beam PP' which is inert from the point of view of heatand to the bottom face of which there are fixed and individually connectedy a strip EE performing a heating action in itself and two non-heating strips LL framingv the heating strip EB parallel thereto. If deemed appropriate, a heat-insulating materialrnay, if required, be packed between the heating strip EE and the non-heating strips LL'.

S that this assembly can be placed obliquely in corre-` spondence with the possible over-all Obliquity of the seam to be vulcanized, the jacks V (see FIG; are mounted so as to oscillate on a horizontal shaft O above the axis MM' of the press tableVV (not shown) and fast with the upper .part of the press (not shown) and are connected to the upper face of the beam PP by free articulations such as A,B .and C.

The range in which the appara-tus can be positioned obliquely is symbolised by the chain-dotted lines D1D'1l and D2D'2 (FIG. 4) and the corresponding swung 'positions in which the jacks V are placed are symbolised (FIG. 5) by the chain-dotted lines dld'l and d2d'2, the

jack acting on the middle point B remainingrpertectly vertical in accordance with the chain-dotted line m-m' (FIG. 5).

This constructional form -of an apparatus complying with the principle of the invention permits ofreducing the consumption yof electrical heating energy to a ,minimum and, moreover, it ensures that the parts of the pieces of rubberized fabric respectively in contact withthe two n-onheating strips LL' will not be heated. It should be understood that, in this constructional for-m, no jack necessarily remainsperfectly vertical; The indication of `verticality m-m' given with regard to the middle jack Yarticulated at B has been 'sov given only fordescriptive purposes.

Example 3 This third example is shown in FIGS. 6 and 7, FIG. 6 being a view in elevation 4,of the equipped press and FIG. 7 being an end view ofsaid press in the direction of the arrow IX of FIG. 6.

In this formof construction, the jacks do not oscillate and are connected rigidly to a horizontal support SS' parallel to the beam PP comprising the strip EE' performing a heating `action in itself and the non-heating strips LL' framing said strip parallel thereto (FIG. 7). The horizontal supportrSS' is tted at its tWo .ends into two horizontal recesses G and G' provided in the ends of the frame of the press and in which said support SS' can be shiftedand oriented `as required (while remaining in the same horizontal plane) with-respect to the axis vtof the table T of the press. Y Y v Thi-sform of construction entails a suitable design of the end elements forming the frame of the press. This cannot, in any case, be regarded as a drawback, inasmuch as they frames yof certain modern presses, such as those used, Ifor example, for the Ishaping of aeronautical elements, are commonly constituted by an assemblyV of standardised partial frames inserted and assembled in any suitable number, variable as required, betweentwo terminal frames comprising all the means and members for operating the Vassembly thus formed. Y

Example 4 This -fourth example of embodiment'is Vshown in FIGS. 8, 9 and l0, FIG. 8 being a plan view of therapparatus without the jacks V, FIG. 9 being ya lsection on the line XI-XI of FIG. 8 and FIG. 10 being a section on the line XIIf-XIIof FIG. 8.

Inthis constructional form, the two non-heating elements `FF' ensuring the holding of the pieces of rubberized fabric constitute the parallel edges of a' horizontal framework braced by cross pieces l and I., the latter being fast with the jacks V andV said non-heating element-s FF remaining .always parallel to the axis of the table of theV press (not shown) whatever-'the relative obliquity of the seam to be vulcanized. On the other hand, the element PP' performing a heating action in itself isadapted to be shifted as required within the above-described framework.

It should be understood that the examples described above cannot in any case be interpreted'in the sense of limiting the scope of the invention and that the ter-m pieces of rubberized fabricv adopted in describing them covers all those thin rubberized elementscapable of being welded together by hot vulcanization. Y

It Vshould likewise be understood that thev invention is independent :of -all questions of dimensions, the nature of the .materials employed for .constructing an apparatus, detail-s of construction of an apparatus, theV type of jacks employed and the configuration ofthe press and all auxiliary devices to be provided for working the press so equipped Iand controlling the vulcanization temperatures,

provement comprising in combination Ia table adapted to support said two rubberized sheetlike elements in adjoining position; a beamlike member mounted above said table for vertical reciprocating movement into .and out of engagement with the sheetlike elements resting upon said table; an elongated heatable platen placed on the side of the lbeamlike member facing the table7 said platen having a Width substantially equal to that of the seam; a thermically insulated holding ledge on each side of said platen, said ledges adapted to hold the seam forming border portions -of said element-s during vulcanization, and means to shift said platen upon the beamlike member comprising strap supports fastened at each end to the side near the end lof said beamlike member and being spaced a small distance from the end of said member, shaft-s having one end attached to said platen and passing between said member and said strap supports and 'handles attached to the other end of said shafts.

2. In an apparatus for heat-vulcanizing an elongated seam between two rubberized sheetlike elements the improvement comprising in combination a table adapted to support said two rubberized sheetlike elements in adjoining position; a beamlike member mounted above said table for vertical reciprocating movement into and out of engagement with the sheetlike elements resting upon said table; an elongated heatable platen placed on the side of the beamlike member `facing the table, said platen having a width substantially equal to that of the Seam; a thermically insulated holding ledge on each side of said platen, said ledges adapted to hold the seam forming border porti-ons of said elements during vulcanization, `and means to shift laterally the platen along said beam within the contines of said beam whereby the platen can be shifted to bring said platen into operative relationship as to any oblique position of the seam formed by said rubberized sheetlike elements.

References Cited by the Examiner UNITED STATES PATENTS 2,638,964 5/53 Andina 156-580 X 2,698,273 1,2/54 Miner et al `156-583 X 2,766,365 10/56 Winstead 156-583 X 2,834,395 5/58 Russell et al 156-583 3,026,237 3/62 Gulvis 156-583 EARL M. BERGERT, Primary Examiner.

DOUGLAS I. DRUMMOND, Examiner. 

1. IN AN APPARATUS FOR HEAT-VULCANIZING AN ELONGATED SEAM BETWEEN TWO RUBBERIZED SHEETLIKE ELEMENTS THE IMPROVEMENT COMPRISING IN COMBINATION A TABLE ADAPTED TO SUPPORT SAID TWO RUBBERIZED SHEETLIKE ELEMENTS IN ADJOINING POSITION; A BEAMLIKE MEMBER MOUNTED ABOVE SAID TABLE FOR VERTICAL RECIPROCATING MOVEMENT INTO AND OUT OF ENGAGEMENT WITH THE SHEETLIKE ELEMENTS RESTING UPON SAID TABLE; AN ELONGATED HEATABLE PLATEN PLACED ON THE SIDE OF THE BEAMLIKE MEMBER FACING THE TABLE, SAID PLATEN HAVING A WIDTH SUBSTANTIALLY EQUAL TO THAT OF THE SEAM; A THERMICALLY INSULATED HOLDING LEDGE ON EACH SIDE OF SAID PLATEN, SAID LEDGES ADAPTED TO HOLD THE SEAM FORMING BORDER PORTIONS OF SAID ELEMENTS DURING VULCANIZATION, AND MEANS TO SHIFT SAID PLATEN UPON THE BEAMLIKE MEMBER COMPRISING STRAP SUPPORTS FASTENED AT EACH END TO THE SIDE NEAR THE END OF SAID BEAMLIKE MEMBER AND BEING SPACED A SMALL DISTANCE FROM THE END OF SAID MEMBER, SHAFTS HAVING ONE END ATTACHED TO SAID PLATEN AND PASSING BETWEEN SAID MEMBER AND SAID STRAP SUPPORTS AND HANDLES ATTACHED TO THE OTHER END OF SAID SHAFTS. 